Which of the following is the correct syntax to define a simple state schema class with a single string field username in Langchain?

easy📝 Syntax Q3 of 15

LangChain - LangGraph for Stateful Agents

Which of the following is the correct syntax to define a simple state schema class with a single string field username in Langchain?

Aclass UserState: username: str

Bclass UserState: def username(self): return str

Cdef UserState: username = str

Dclass UserState: username = str()

Step-by-Step Solution

Solution:

Step 1: Review correct class attribute syntax
Defining a class attribute with type hint uses username: str inside the class body.
Step 2: Check other options for syntax errors
Defining username as def username(self): return str creates a method instead of a field. Using def UserState: is invalid syntax for a class. Assigning username = str() sets an empty string instance instead of using a type hint.
Final Answer:
class UserState:\n username: str -> Option A
Quick Check:
Correct class attribute syntax = class UserState: username: str [OK]

Quick Trick: Use type hints for fields inside class, not methods [OK]

Common Mistakes:

MISTAKES

Master "LangGraph for Stateful Agents" in LangChain

9 interactive learning modes - each teaches the same concept differently

Want More Practice?

15+ quiz questions · All difficulty levels · Free

More LangChain Quizzes